Theftproof lamp socket



March 19, 1940.

THEFTPROOF LAMP -S0=CKET Filed April 6, 1938 L. soKoLoFf 2,194,329

Patented Mar. 19, 1040 2,194,329 THEFTPROOF LAMB SOCKET 7 Louis Sokoloif, Chicago, Ill. Application April 6, 19ss,s ria11vo.200,2s7

11 Claims. r01. 173-356 UNiTED T The presentinvention relates in general to electric sockets such as utilized for electric lamps and the like was in particular concerned with improved means for preventing removal of the lamp from the socket, and thus preventing unauthorized persons from stealing the lamp, replacing it with a larger one or connecting electrical devices such as heaters, cookers, curlinig irons and the like with the lamp socket, hence guarding against the loss of the lamp andthe utilization of. an excessive amount of electric current.

A further object of the invention is to provide an improved plug and socket attachment which may be utilized with any type of screw socket and may be permanently attached thereto by simply screwing it into the socket, and which is arranged to work efficiently with sockets of different depths.

A further object is to provide an improved de- 'vice of the herein described character having a combined plugand swivel socket which are both accessible for gripping with the fingers when screwing the plug part into the lamp socket or the lamp into the swivel socket of the device,

but which may be rendered inaccessible when attached to the lamp socket.

A further object is to provide a lamp socket having aprotective casing split in an axial die rection, and improved means for securing the parts of the casing or shell together.

A still further object of the'invention is to provide an improved plug having selectively operable means for lockingv and unlocking a screw plug or other electrical connecting device against their removal from an associated socket into which it has been screwed.

Another object of the invention is to provide in an improved socket for a lamp or the like having a swivel shell and spring pressed central contact, an improved arrangement in which the spring action of the central contact is utilized to maintain pressure engagement between movable current carrying parts in the circuit connections of the shell.

It is also an object to provide' in a screw connecting device,. a rotatably. mounted collar at I the base of the screw shell, whereby a tool such as a screwdriver cannot be utilized to forceably remove the plug by driving. the tool into the base portion of the screw shell.

Other objects and features of the invention will more fully appear from the following detailed description takenin connection with "the "PATENT" oFFrcs accompanying drawing, which illustrates a single embodiment thereof, and-inwhich:

Figure l is a view in elevation of a theft proof lamp socket embodying the features of the present invention, a lamp being secured therein;

Figure 2 is an enlarged central longitudinal sectional view of the same, certain of the parts being shown in elevation; Figure 3 is a fragmentary section taken sub stantially on line I.IIIII of Figure 2; v

Figure 4 is an enlarged transverse sectional view, taken substantially on line IVIV of Figure 1; I

Figure 5 is an enlarged view in elevation of the plug end of the device, showing details of the locking mechanism; and

Figure 6 is a traverse sectional view through the same, taken substantially on line VI-VI of Figure 5.

As shown on the drawing:

While the present invention may be utilized with any type of electrical screw socket, for pur poses of illustrating the invention it has been shown as being applied to a socket. of the pendant type as generally indicated at A. This socket is of the usual construction containing a threaded shell Ill, and central spring contact llior making the electrical connections with a lamp connection plug or the like which'may be screwed into the socket.

As clearly shown in Figure '2, my invention comprises a plug body portion l2 ofinsulating material such as Bakelite, porcelain or the like, which is of generally circular cross section. This body at one end is formed to provide a diametrically extending end projection 13, and at its other end is expandedto form a circumferentially e'xtending flange M which defines an abutment shoulder l5 facing toward the Opposite end of the plug body g This flange is peripherally knurled as shown in Figure 5. The knurled flange provides a gripping portion by: means of which the plug body'may be rotated when connecting it with asuitable socket. 1 v I Surrounding the opposite end portion of the plug body is a threaded shell which is'deflected at one end to form diametrically opposed inwardly extending segmental flanges l1 and [8 having straight inner edges adapted to lie adjacent the sides of the end projection l3, when the shell isassembled on the plug body.

disposed at the flanged end of the plug body. These screws extend through appropriate openings in the flanges I1 and I8. Each screw is'provided with a nut 2I disposed adjacent its head and adapted to be seated in a recess 22 at the flanged end of the plug body, and a nut 23 adapted to be screwed onto the other end of the screw and bear against the associated segmental flange of the shell I 6. It will be noted that the nuts 2i and 23 cooperate to tightly secure the shell to the plug body.

The end of the shell I6 which is disposed towards the flanged end of the plug body does not extend to the shoulder I5 but is spaced therefrom. Extending between this end of the shell I6 and the shoulder I5 is a protective annular sleeve member 24, which is preferably constructed of a hard metal such as steel, this member being rotatively supported on the plug body for a purpose which will later be explained in detail.

Swivelly supported at the flanged end of the plug body is a threaded socket shell 25 whichis adapted to have a lamp base or other electrical screw connection screwed thereinto.

The shell 25 is deflected at one end to form an inwardly extending flange 25 which overlies and makes surface engagement with an annular contact washer 27 which is provided with threaded openings for receiving the bolts l9 and 20 and permitting the bolts to have their head portions tightened against the under surface of the washer. It will be apparent that by adjustment of the nuts 2| on the bolts I9 and 25, the spacing between the washer 21 and the flanged end of the plug body maybe adjusted so as toprovide for limited axial movement of the shell 25.

Surrounding the shell 25 is the usual insulating sleeve 21a of suitable material which provides a gripping surface and which prevents contact with the shell 25. 7

With the arrangement just described, one side of the electric circuit will be carried from the shell III of the lamp socket A, through the shell I6, the bolts I9 and 20, through the washer 2?, and then to the socket shell 25,.

The other side of the circuit will be carried from the central contact I I of the lamp socketA through a bolt 28 to a central spring contact 29 which so positioned asto make electrical contact with the central contact of the lamp base or other electrical connector which may be screwed into the socket. a

The head of the screw 28 is seated in a countersunkportion of a washer 30 which bears on the end projection I3. The screw extends through a suitable central bore in the plug body and is threaded at its endfor receiving a suitable nut 3 I. The contact 29 is of generally Ll-shaped construction and has one leg disposed between the nut 3| and the bottom of a recess portion 32 in this end of the plug body. By having this leg of the contact 29 disposed in the recess, the contact is held against rotative movement. It will be noted that the other leg of the contact projects into the associated end of shell 25 through the opening defined by the annular washer 21.

In connecting the device with a lamp socket,;

it will be noted that the plug portion maybe directly screwed into the shell It by grasping the knurled flanged portion of the plug body. The

plug may be screwed tightly home in the socket.

The sleeve 2'I a which surrounds the swivelly mounted shell 25 of the socket portion of the device may now be tightly gripped and held against rotative; movement while screwing an electrical,

, axially extending device, or an'electric lamp as indicatedat 33 intothe shell 25. Since both the shell and lamp may be gripped by the operators hand, the lamp may be screwed tightly home in the socket.

It will be noted that as the central connection of the lamp engages the spring contact 29, the action of this spring will tend to axially move of the lamp from its associated socket or the device from the pendant socket A, there is provided a protective shell 34 of suitable material, and which may be of insulating material such as Bakelite or the like, which is adapted to extend over and conceal against access the knurled flange It and the sleeve 21. In so doing, the'swivel connection between the plug portion and socket portion of the device is rendered inaccessible i The shell or casing 34 is of generally tubular flanges 35 and 36 at its ends.

With the casing 34 assembled asshown in Fig: ure 2, the flange 36' will overlie the flange'III of the plug body and the inner construction having inwardly extending annular- 26. The other flange, namely flange 35, will be edge of the flange 36 will be disposed adjacent theprotectivesleeve over the associated end of the insulating sleeve-27.

The casing 35', as shown in Figure 4, is preferably formed of two sections 916a and 3 51) which have their ends in abutting relation to form an joint on either side ofthe casing. These sections may belloeked together in any suitable manner to prevent the casing from being removed from the is not authorized or who suitable key or the like. v

For this purpose I have utilized locking bolts 35 which extend through lugs 35 and 3'! formed on the respective sections. f

Oneof'these lugs is providedwith a passage 38 through which the shank of the bolt extends,

is not possessed with a device by anyone who this passage being in registration with athreaded socket 39 in the other lug into which the bolt may be screwed.

The head of the bolt is made of polygonal.

shape and is adapted to be seated in a suitable socket or recess 45 so as to necessitate the use of a, properly designed socket wrench orkeyin order to remove the locking bolt and disassemble the casing 3E1so'that it may be removed.

While I have disclosed diametrically disposed locking bolts on either side of thecasing 3 4,"it will be apparent to those skilled in the. art I that if desired, the sections of the casing may be hinged along one joint. and secured by a locking belt at the other joint in themanner'just described. 'f I vSillifiitht Pl portion of the device hasbeen screwed home and is tightly secured in the sock et A, and the lamp is likewise tightly screwed into socket 25, any endeavor of a person to remove the lamp, when' the protective casing t lisi in position as shown in Figure 2, will simply result' ina swivelling or rotating or the shell '25.

It is therefore impossible to directlyapply a force to, the device either to remove the 'lampor remove the device from thesocket A. I

Sockets as now constructed vary in depth so that. in screwing, the. plug portion of the device into. different; sockets it. will project. more. or less from the,-1,1di.0f the socket leaving a space .be- 75 tween the flange 36 of the casing 34 and the socket. Under such circumstances it might be possible for a person who desired to steal the device or remove it from the socket A to insert an instrument or tool such as a screwdriver into this spa eand forcibly rotate. the plug portion of the d'vice and thus remove it from the socket A." I l I I In my improved arrangement, such removal of, the device isv prevented by the protective sleeve 24 which is rotatably mounted on the plug body. It will be evident that any endeavor to drive the instrument or tool into the plug portion as just. explained, will simply rotate this sleeve and foil the attempt to remove the device from theassociated socket A. I

Since there may be installations in which it may be desired to prevent removal of the device, once it has been attached to a socket, I have provided a selective locking arrangement so that the, plug portion of the device may or may not be locked in the associated socket as desired.

As shown, principally in Figures 5 and 6, this locking device comprises a curved dog member 4| which is mounted for swinging movement within a-recess 42 in the plugbody, the dog memberbeing pivoted atone end on the bolt 20 which extends through this recess. The shell 16 is cut out, as shown at 43, along a portion of its thread in order to provide a communication between the recess, 42 and the exterior of the shell l6.

,As shown in Figure 6, the dog may be swung to a position as shown in full lines wherein the outermost end of the dog projects outwardly past the bottom of the thread of the shell, or may be swung to a position as shown in dotted lines, wherein the outermost end ofthe dog is disposed below the bottom of the thread and withinthe recess 42;

The outermost end of the dog is preferably bevelled inform a point as shown at 44 which,

when the dog is in locking position, will follow the thread of the socket shell into which the plug portion of the device may be screwed.v

With'the dog in locking position, as shown in full lines, the plug portion of the device may be screwed into a socket.

tion thereof will tend to rotate the dog about its pivotand force its pointed end into the shell of the socket and thus oppose removal or unscrewing of the plug portion. -.It will be noted in the socket so that the plug portion may be easily screwed into the associated socket and removed without the dog taking effect to prevent such removal.

From the foregoing description, it will be apparent that the present invention provides an improved plug and socket attachment which may be utilized with any type of screw socket;

which will work efficiently with sockets of different depths; which embodies a combined plug and swivel socket which are normally accessible I However, attempt to i remove the device by unscrewing the plug porfor' grippingwith the fingers when connecting the device to alamp socket, but which may be rendered inaccessiblewhen desired by a locked casing; an electrical connector having a protective casing split in axial direction with improved means for securing the casing parts together; which contains selectively operable locking means, whereby the device may be selectively connected to an associated socket and lock or unlocked relative thereto as desired; which utilizes the spring pressure of the central contact for actuating and maintaining good electrical contact between movable parts of the swivel socket; and which embodies an improved rotatably mountedsleeve or collar at the base of the plug portion, whereby an instrument or tool such as a screwdriver cannot be utilized to forcibly remove the plug portion from the associated socket.

It is of course to be understood that although I have described in detail the preferred embodiment of my invention, the invention is not to be thus 'limited, but only insofar as defined by the scope and spirit of the appended claims.

I claim as my invention:

'1. A combination electric connector comprising a screw-threaded plug. member adapted to be screwed into a socket receptacle, a screwthreaded socket member having a swivel connection with said plug, said members havinggripping surfaces extending substantially their entire circumferences, said surfaces being exposed when the plug is screwed into said receptacle, whereby the members may be held and rotated, a casing swivelly mounted on said plug and having a plurality of complementary sections, and means for locking said sections together in assembled relation over said surfaces after the plug is screwed into a socket receptacle for rendering said surfaces inaccessible.

, 2. A combination electric connector comprising a screw-threaded plug member adapted to be screwed into. a socket receptacle, a screwthreaded socket member having a swivel connectionwith said plug, said members having gripping surfaces extending substantially their entire circumferences, said surfaces being exposed when the plug is screwed into the receptacle,

.Whereb'y'the members may be held and rotated,

said members, said members having gripping surfaces exposed when the plug member is screwed into a socket, whereby the members may be held and rotated, a swivelled split casing disposable around said members for concealing said swivel connection and rendering said sur-' faces inaccessible, and key actuated means for securing the parts of the split casing in assembled rigidly interlocked relation around said members and preventing removal thereof.

4. An electric connector adapted to be utilized with sockets having threaded shells supported at different depths below the open end of the socket,

shell swivelly associated with said plug, a circumferentially extending gripping surface at the exposed end of the plug, when it is screwed into a socket shell, a rotatably mounted substantially said connector comprising a screw plug, a socket I impenetrable ring adjacent said surface and of such width as to extend into the open end' of the socket under different depth conditions. of the socket shells, and a swiveled protective casing extending over the gripping surface and said socket shell and overlapping the outer edge margin of said ring, said ring preventing unscrewing of the plug by inserting a tool in any space existing between the adjacent ends of the casing and socket. a

5. An electric connector adapted to be utilized with sockets having threaded shells supported at different depths below the open end of the socket, said connector comprising a screw plug, a socket shell swivelly associated with said plug, a circumferentially extending gripping surface at the exposed end of the plug, when itv is screwed into a socket shell, a rotatably mounted substantially impenetrable ring adjacent said surface and of such width as to extend into the open end of the socket under different depth conditions of the socket shells, and a sectionalized rotatably mounted casing locked in assembled relation over the gripping surface and said socket shell and overlapping the outer end marginof said ring, said casing sections when unlocked being removable laterally while the plug is screwed in the socket.

6. An electric connector adapted to be utilized with sockets having threaded shells sup-ported at different depths below the open end of the socket, said connector comprising a screwplug, a socket shell swivelly associated with said plug, a circumferentially extending gripping surface at the exposed end of the plug, when it isscrewed into a socket shell, a rotatably mounted substantially impenetrable ring adjacent said surface and of such width as to extend into the open end of the socket under different depth conditions of the socket shells, and a directly engageable locking member carried by the plug and mounted for selective movements for presetting it, prior to screwing the plug into a socket shell, in a position to lock the plug permanently against removal from the socket and a position enabling removal of the plug therefrom.

- 7. Means for preventing unauthorized removal of an electric bulb from an element joined to a circuit, including a screw shell, means mounting the shell on the element for free rotation thereon, and having electric connection therewith, said shell being adapted to have the electric screwedtherein, an axially split tubularcasing rotatable on said element, and means for locking the parts of the casing together on the element about the shell to prevent access to said shell.

I 8. A screw plug having electrical contact portions and adapted for threaded engagement with" a socket, said plug having a selective element thereon movable between locking and nonlocking positions for respectively opposing and permitting disengaging movements of said plug relative to said socket, said plug member whensaid element is in looking position and inengagement With'a socket becoming permanently secured therein, and said element being then rendered non-operable for selective positioning,%a socket carried by said plug, and lockable means to prevent removal of a bulb from said socket.

9. A theft proof lamp lock adapter, comprising a screw plug having electrical contact portions and adapted to be screwed into a socket, said plug having means operable upon screwing the plug into the socket to join the plug to said socket so as tobecome a permanent part thereof, a shell rotatably supported ,by said plug" into which a lamp may be secured in electrical connection with the said contact portions, and means engaging I said plug and-covering said shell to prevent the theft of said lamp from said shell. 1 I

10. A theft proof lamp lock adapter, comprising a screw plug having electricalcontact portions and adapted to be screwed into a socket, said plug having means operable upon screwing the plug into the socket to join the plug to said socket soas to become a permanent part thereof,

a shell carried by said socket and adapted to sup-' port a lamp in a manner so that theft of the lamp therefrom is prevented, a casing associated with said plug and covering said shell and arranged to prevent the theft of a lamp from said shell:

11. A theft proof lamp lock adapter compris ing a unit having a plug at one end thereof adapted to be connected with a socket to provide an electrical connection, means'at the other end of said plug for mounting a lamp to establish an electrical connection therewith, means that permanently affixes itself to said socket to prevent removal therefrom, and guard means for preventing unauthorized removal of said lamp front 4 H its mounting. LOUIS SOKOLQFF. 

